Architecture & practice·Judgement and reasoning traps
the team wrote its own scheduler because the existing one did not fit exactly, and now maintains a scheduler.
Not invented here
Also calledNIH syndrome
Rejecting external solutions in favour of building your own, usually justified by a genuine but minor misfit. The build is systematically undercosted because the ongoing ownership — bugs, upgrades, documentation, the person who leaves — is not counted at decision time. The mirror-image trap is real too: adopting a dependency for something that would be forty lines is its own permanent cost.